1. Field of the Invention
This invention relates to a copper-modified cellulose fibrous material which is water absorbent and possesses deodorizing and microbistatic properties. Fibrous materials such as these are of considerable value for numerous medical, hygienic, cosmetic and esthetic applications.
2. Statement of the Related Art
It is known that, in articles applied to the surface of the body, particularly in areas of the body where perspiration is heavy or where bodily secretions, such as blood or urine, are discharged, bacterial decomposition of the secretion occurs after only a short time under the effect of ubiquitously present bacteria. This bacterial decomposition is accompanied by the emission of unpleasant odors and, in many cases, leads to dangers through the growth of pathogenic microbes.
Accordingly there have been numerous attemps to provide fibrous materials with microbistatic and deodorizing properties. Known microbicides and deodorants, such as iodine, phenols, thiophenols, quaternary ammonium compounds, antibiotics, nitro compounds, formaldehyde and heavy metal compounds, have been proposed for this purpose. One of the greatest problems in this regard is fixing the active substance to the fibers. Copper compounds have also been proposed for this purpose.
U.S. Pat. No. 4,385,632 (and corresponding German published application No. 31 35 410) describe an absorbent padding of nonwoven cellulose fibers or wadding which is sprayed with an aqueous solution of a copper salt or prepared from fibers or wadding pre-treated with such a solution. Disclosed suitable copper salts are the borate, sulphate, chloride, formate, oxalate, tartrate, citrate, lactate, and especially, the acetate. This known material is attended by various disadvantages. Thus, the copper salt is not uniformly distributed in the absorbent padding, some of the copper salt crystallizes out after drying (which gives rise to difficulties during processing of the fibrous material), and the copper salt dissolves in the presence of water, for example, in a wet diaper or in a damp tampon, and can thus reach the surface of the skin in relatively high concentrations and produce undesirable reactions.
Published European patent application No. 19,371 describes a blood-coagulating absorbent material which consists of a water-swellable, covalently crosslinked anionic polyelectrolyte, for example crosslinked carboxymethyl cellulose, which is treated with transition metal ions, such as with copper ions. Disclosed salts for treatment include copper chlorides, nitrates, sulphates, and acetates in one process, and copper carbonates, oxides or hydroxides in a second process. However, materials such as these are not usually fibrous or cannot readily be converted into fibers, wadding or nonwovens. It is disclosed that the materials may be processed with a fibrous carrier as a support when used in hygiene aids. Both the manufacture and also the processing of this material are difficult.